Radar 3

Question 1

Describe common radar systems.

Answer 1

Search - A search radar must scan a volume of space at regular intervals to locate targets.
* The radar beam is scanned repeatedly over that entire volume.
* Search radars maybe also referred to as Surveillance or Acquisition Radars

Tracking - Target tracking requires greater accuracy and higher data rates.
* Tracking RADARs use narrow beams to follow a target in track.
* Tracking RADARs provide continuous update of target range, azimuth and elevation.
* Tracking RADAR normally works in conjunction with search RADAR.

Question 2

Describe common radar antenna radiation patterns.

Answer 2

The RADAR function determines the antenna radiation pattern required.
* The physical shape of the antenna will determine the radiation pattern.
* The physical size of the antenna will be determined by the Radio Frequency.

Can either be Pencil Beams, Fan beams or Shaped or Spoiled Beams

Question 3

State the characteristics of Parabolic Radar Antennas

Answer 3

The true parabolic antenna shape focuses the radiation from the feed into a pencil beam.
* Different reflector shapes can be used to form differing beams patterns.

Question 4

State the characteristics of Casse Grain radar antennas

Answer 4

Contains 2 reflectors.
* Feed at the rear of the primary reflector
* A secondary reflector focuses radiation on the primary reflector for beam forming.

Question 5

State the characteristics of Slotted Waveguide radar antennas

Answer 5

The slotted waveguide is comprised of a number of slots cut into a single waveguide.
* If the slots are arranged in a line the antenna is referred to as a linear array.
* Energy is fed into one end of the waveguide and propagates from the slots cut in the waveguide face.
* The slots are spaced at approximately 1/2 wavelength such that the slots fall within each others induction field.
* The fields interact to produce a radiation pattern that is the sum of the individual slots (elements).

Question 6

State the characteristics of Planar Array antennas

Answer 6

Single transmitter/receiver
* Multiple antenna radiator elements
* Each element is in phase
* Beam forming achieved by element selection
* Mechanically scanned

Question 7

State the characteristics of Phased Array antennas

Answer 7

Single transmitter/receiver
Each element can be phase shifted independently
Multiple beam shapes
Electronic Scan

Question 8

State the characteristics of Active Array

Answer 8

Each element is a separate Tx/Rx
* Electronic Scan
* Multiple Beam shapes
* Graceful degradation
* Higher efficiency

Question 9

State the characteristics of Conformal Array

Answer 9

Conformal arrays are antenna arrays shaped to fit the object they are being
attached to.

Question 10

With the aid of a diagram describe Cicrular Scan

Answer 10

Question 11

With the aid of a diagram describe Bi-Direcitonal Sector Scan

Answer 11

Question 12

With the aid of a diagram describe Uni-Directional Sector Scan

Answer 12

Question 13

With the aid of a diagram describe Helical Scan

Answer 13

Question 14

With the aid of a diagram describe Raster Scan

Answer 14

Question 15

With the aid of a diagram describe Conical Scan

Answer 15

Question 16

With the aid of a diagram describe Spiral Scan

Answer 16

Question 17

With the aid of a diagram describe Track While Scan (TWS)

Answer 17

Question 18

With the aid of a diagram describe Sequential Lobing

Answer 18

Question 19

With the aid of a diagram describe Lobe on Receive Only (LORO)

Answer 19

Question 20

With the aid of a diagram describe Conical Scan on Receive Only (COSRO)

Answer 20

Question 21

With the aid of a diagram describe Monopulse

Answer 21